Tension relief foam and mattress constructions

ABSTRACT

Engineered foam components for mattresses reduce tension forces in the foam and in the horizontal plane or block planar pieces, and improve the conformance and motion separation characteristics of foam support systems. The tension relief foam pad is a generally rectangular piece of foam having a top surface and a bottom surface. The length and width measurements of engineered foam pieces are substantially equal to that of a mattress with which it is to be used. Depending on the arrangement of the tension relief foam pad within the mattress construction, either the top or bottom surface contains a plurality of continuous cuts, slits or openings arranged in a checkerboard or other patterns with an opposite planar uncut surface.

RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent Application No. 61/485,364, filed on May 12, 2011, which is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present invention is in the field of reflexive support systems including support systems for humans such as bedding or seating.

SUMMARY OF THE INVENTION

The present invention incorporates surface or structurally modified foam into a mattress for highly localized deformation and support, independent movement and reduced tension in the horizontal plane, an improvement in conformance and motion separation characteristics of the support system. In a representative embodiment, a tension relief foam pad is a generally rectangular piece of foam having a top surface and a bottom surface opposite and parallel to the top surface with four side wall which are perpendicular to and extend between the top and bottom surface. The length and width measurements of the pad are substantially equal to that of a mattress with which it is to be used. Depending on the arrangement of the tension relief foam pad within a mattress construction, discussed in greater detail below, either the top or bottom surface contains a plurality of cuts arranged in a checkerboard or other pattern, while the opposite surface is substantially planar. The cuts create a plurality of square or rectangular blocks on the surface of the pad and independent modules which have independent support characteristics, and which may be coupled with other support elements such as springs.

DESCRIPTION OF THE DRAWINGS

FIG. 1A is a perspective view of a preferred placement of a tension relief foam topper among other foam layers in a mattress system.

FIG. 1B is a perspective view of an alternate placement of a tension relief foam pad among other foam layers in a mattress system.

FIG. 2 is a side view of one embodiment of tension relief foam pad and innerspring.

FIG. 3 is a side view of an alternate embodiment of tension relief foam pad and innerspring.

FIG. 4 is a chart showing the surface deflection on a tension relief foam pad in various locations among other foam layers in a mattress system.

FIG. 5 is a chart showing the surface strain on a tension relief foam pad in various locations among other foam layers in a mattress system.

FIG. 6A is a perspective view showing the stress distribution across a tension relief foam pad when the pad is used as a top layer of a mattress system.

FIG. 6B is a perspective view showing the stress distribution across a tension relief foam pad when the pad is used as a bottom layer of a mattress system.

FIG. 7 is a side view of an alternate embodiment of tension relief foam pad and innerspring.

FIG. 8 is a top view of a tension relief foam pad with non-uniform sized blocks.

FIG. 9 is a side view of one embodiment of tension relief foam pad with non-uniform sized blocks.

FIG. 10 is a side view of an alternate embodiment of tension relief foam pad with non-uniform sized blocks.

FIG. 11 is a side view of an alternate embodiment of tension relief foam pad with non-uniform sized blocks.

GENERAL DESCRIPTION OF PREFERRED AND ALTERNATE EMBODIMENTS

The tension relief foam pads, mattresses and support systems of the present disclosure and related inventions utilize surface modified foams to achieve independent and localized deformation, support and movement and reduced tension or shear forces in the horizontal plane, benefitting the conformance and motion separation characteristics of the system. The various forms of tension relief foam pieces and pads described herein (also referred to herein as “pad” or “foam pad” or “topper”) 10 are generally in the form of rectangular block planar shapes having a top surface and a bottom surface opposite and parallel to the top surface. For example, the length and width measurements of the pad 10 are substantially equal to that of a mattress with which it is to be used. Although described with reference to particular representative embodiments, it is understood that the concepts of the present disclosure can be applied and implemented in other physical forms of foam. As used herein, the term “tension relief foam” refers generally to each of the various described foam configurations and constructs, and more generally to foam body configurations which reduce or eliminate stress forces within the cellular structure of a body of foam. The design concepts and configurations are equally applicable to any type of foam from which such shapes and configurations can be manufactured, including open cell and closed cell type foams. Depending on the arrangement of the tension relief foam pad 10 within the mattress construction, set forth in greater detail below, either the top or bottom surface contains a plurality of continuous cuts 18 arranged in a checkerboard or other pattern, while the opposite surface is substantially planar and generally without cuts. The cuts 18 create a plurality of square or rectangular blocks 16 on one surface of the pad 10.

A typical mattress system includes a foundation or box spring, a support unit and optionally, a comfort unit. The foundation can be of conventional internal design and construction, having a rectangular frame on which are mounted a plurality of spring elements or modules to provide flexible support for an overlying grid, which defines the foundation surface. The spring modules in the foundation may be formed of wire or made of a composite material, or be entirely without individual spring modules and rather in the form of a flexible support surface. Foundation units are typically supported by a bed frame which may further include side boards, a head board and foot board. The support unit or innerspring of the mattresses of the disclosure are dimensioned to fit upon the foundation surface and be fully supported thereby. The support unit or innerspring may be of conventional design, containing a plurality of interconnected spring coils. The support unit may alternatively be a high performance foam core structure without any internal wire or spring elements. The support surface has relatively few layers of material, which cover the innerspring, such as one or more layers of mat or foam or other sheet-like fabric or non-woven material. The primary purpose of layers is to provide a smooth surface over the ends of the coils of the innerspring. A comfort unit is dimensioned to fit upon the support unit. It has a generally horizontal top and bottom and generally vertical or tapered sides extending between the top and bottom to define a central space containing supporting and cushioning components. The comfort unit contains additional layers of compressible, conformable internal layers of materials. A comfort unit may contain one or more foam core layers and intermediate and outer layers made of matted material, synthetic or organic, such as cotton or wool fibers, polyester, or hybrid material mats. Extra material layers may also be used, such as woven cotton, wool or synthetic cloths or hybrids thereof, or sheet materials such as plastic films, solid or perforated, which may serve as moisture barriers, aeration promoters, liners or flame or heat retardants. The feel of the comfort unit may be adjusted by using different insert materials such as polyurethane foams, visco-elastic foams, latex foams, fibers, gels or various combinations thereof. The comfort unit materials are encapsulated by upholstery, which may include ticking, for example foam or padding backed woven or embroidered material, side wall material or ticking, tape edges, and a gusset which extends from the pillowtop to the top of the support unit. The upholstery of the comfort unit may be a combination of materials.

In a preferred embodiment, the top surface of the tension relief pad 10 is generally planar while the bottom surface contains a plurality of cuts 18 arranged in a checkerboard or other pattern. The cuts or voids 18 between discrete islands of foam can be uniform in size and spacing or not, generally linear or not, and dimensioned uniformly or not. The foam structures 16 can be formed by molding, cutting, water-jet forming or by any other suitable process. When used in combination with an innerspring 15 or spring unit, the tension relief foam 10 pad is generally placed directly above the innerspring 15 and below any other foam layers 12 of the mattress or comfort unit, as shown in FIGS. 1A, 2 and 3. A thin fabric or fiber layer or insulation layer may be located between the tension relief foam pad 10 and the innerspring 15. The individual blocks 16 on the bottom surface of the pad 10 may be aligned with or correspond in location to the positions of the upper terminal convolutions of the coils 14 of the mattress innerspring 15, as shown in FIGS. 2 and 3. Depending on the size of the blocks 16, each block may correspond and work in combination with two or more springs or coils 14 of the innerspring 15 to provide improved independent movement of the foam 10 and coils 14 accentuating the feel of the coils 14. Each of the individual blocks 16, in combination with the innerspring 15, is separately compressible in response to the weight placed directly thereon. Placing the tension relief pad 10 directly on top of the innerspring 15, below other foam layers 12, is shown to provide more local compliance, a lower surface strain and a lower complex stress state, as shown in the charts of FIGS. 4 and 5 and on the stress state mapping shown in FIG. 6B.

Representative and non-limiting examples of springs which can be used in the tension relief foam mattress system of the present invention include those disclosed in the commonly assigned U.S. Pat. Nos. 4,535,978; 4,726,572; 5,558,315; 6,134,729; 6,354,577; 6,406,009; 8,178,187; 7,404,223; 7,908,693 and any other spring or reflexive device or devices which could be mounted upon a frame or platform and support a grid or other mattress support structure over the frame or platform. The springs may be individually pocketed or Marshall-type coils or the coils may be without a pocket or encasement. Each of the individual foam blocks 16 may be associated with one or more corresponding spring 14 of a spring unit 15, as shown in FIGS. 2, 3 and 7. Having an axial upper end of each coil 14 in direct or indirect physical contact with an opposing face of a foam block 16 provides a hybrid spring combination by which a force applied to the area of a particular foam block 16 is transferred in whole or in part to the corresponding spring 14, and the matched spring 14 or springs and foam block 16 respond together to applied forces. The size of each block 16 in the pattern may be uniform, such as, for example, the pad 10 shown in FIG. 7 wherein each uniformly sized foam block 16 corresponds to a single coil unit 14 of the innerspring 15. Also, FIG. 3 shows a pad 10 with uniformly sized foam blocks 16 correspond to every two coil units 14 of the innerspring 15. Alternatively, the size of the foam blocks 16 in the pattern may be non-uniform, such as, for example, the pad 10 shown in FIG. 2, wherein blocks 16 having a first size, which corresponds to three coil units 14 of the innerspring 15, are interspersed between blocks 16 having a second size which corresponds to two coil units 14 of the innerspring 15. The individual blocks 16 may be zoned such that the blocks 16 vary in number or size. For example, the blocks 16 located along the short edges of the pad 10 may have a larger width while the remainder of the blocks 16 located therebetween may have a uniform width, which is less than the width of the blocks 16 along the short edges of the pad 10. Any pattern of uniform or non-uniform sized blocks 16, which correspond to any number of coils 14 may be used to create different zones in the tension relief foam pad 10 and mattress system of the present invention.

In an alternate embodiment, the bottom surface of the tension relief foam pad 10 is generally planar while the top surface contains a plurality of cuts 18 arranged in a checkerboard or other uniform or non-uniform pattern. In this configuration, shown in FIG. 1B, the tension relief foam pad 10 is typically placed between additional foam layers 12 of the mattress construction. To prevent bunching or sticking between the blocks 16 on the top surface of the tension relief foam pad 10 and the bottom surface of an adjacent foam pad 12, which may result in body impressions, the tension relief pad 10 may be laminated. The cuts 18 may be of any width or opening (or no opening, such as in the form of a slit) or any size width from 1 mm to 10 mm or greater. Also, the cuts 18 may have generally planar and parallel walls or tapered or other shape, and may be formed in straight and orthogonal lines as shown or in other arrangements which have the similar result of relieving tension in the foam piece.

The tension relief foam pad 10 dimensions, block cut and geometry affect the surface deformation, surface strain, stress state upon the layer and deformation modes of the pad 10. For example, if the height of the blocks 16 is too great, it may cause weak points between each block 16, which may be subject to tearing when a force is applied thereto. If the width of the cuts 18 or the gap between each block 16 is too wide, it may cause local depressions on the top surface of the mattress. If the gap 18 is too narrow, there may be too much contact between adjacent blocks 16 preventing independent movement. Also, if the height of the blocks 16 is too high, it may cause bending or deformation of the blocks 16. Therefore, as general overall design considerations, the thickness of the foam pad 10 or the overall solid height of the foam pad 1—must be greater than or equal to 1 inch; the block 16 width must be greater than or equal to the block 16 height or greater than or equal to 2.5 inches; the gap width must be 15% of the smallest block 16 width or less than 0.75 inches.

As an example, a tension relief foam pad 10 may be approximately 3 inches thick with cuts 18 between each block 16 being approximately 2 inches deep or extending approximately 2/3 of the way into the foam pad 10. The individual blocks 16 may have a uniform size, such as 3.75 inches wide by 3.75 inches long with the width of the cut or gap 18 between blocks 16 being approximately 0.25 inch wide. Alternatively, the individual blocks 16 may vary in size such that the blocks 16 located at the short edges are larger than the blocks 16 located therebetween, wherein the blocks 16 located at the short edges of the pad 10 are approximately 7.35 inches wide and the blocks 16 located therebetween are approximately 5.2 inches wide. This example tension relief foam pad 10 enables a zoned mattress construction wherein blocks 16 of different sizes can be formed and located in particular zones or regions where different support characteristics are desired, such as the shoulder or lumbar areas of the mattress where blocks 16 of a relatively larger size may have a relatively greater density and relatively less freedom of individual movement or deformation to provide firmer support which still has the enhanced conformance of the structurally modified foam and a corresponding spring or core unit support. Tension relief foam pads 10 having various thickness measurements are shown in FIGS. 9, 10 and 11.

It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive. Other features and aspects of this invention will be appreciated by those skilled in the art upon reading and comprehending this disclosure. Such features, aspects, and expected variations and modifications of the reported results and examples are clearly within the scope of the invention where the invention is limited solely by the scope of the following claims. 

1. A tension relief mattress system comprising: an innerspring unit having a plurality of interconnected coils arranged in rows and columns; a tension relief pad located directly above the innerspring, the tension relief pad having a top surface which is generally planar and a bottom surface, opposite the top surface, which has a plurality of cuts arranged to form a plurality of square or rectangles thereon; wherein the tension relief pad is at least 1 inch thick, the width of the square or rectangles on the bottom surface is at least 2.5 inches and the distance between each adjacent square or rectangle is less than 0.75 inches.
 2. The tension relief mattress system of claim 1, wherein each of the plurality of square or rectangles on the bottom surface of the tension relief pad sits directly above each of the plurality of interconnected coils of the innerspring.
 3. The tension relief mattress system of claim 1, wherein each of the plurality of square or rectangles on the bottom of the tension relief pad sits directly above at least one coil of the innerspring.
 4. The tension relief mattress system of claim 1, wherein the plurality of square or rectangles on the bottom surface of the tension relief pad are uniform in size.
 5. The tension relief mattress system of claim 1, wherein the plurality of square or rectangles on the bottom surface of the tension relief pad are non-uniform in size.
 6. Then tension relief mattress system of claim 1, wherein a first group of square or rectangles on the bottom surface of the tension relief pad are of a first size which corresponds to three coils of the innerspring unit and a second group of square or rectangles on the bottom surface of the tension relief pad are of a second size which corresponds to two coils of the innerspring unit.
 7. The tension relief mattress of claim 1, wherein the square or rectangles located on a short edge of the bottom surface of the tension relief pad have a larger width than the remainder of the blocks located therebetween.
 8. The tension relief mattress of claim 1, wherein the space between each adjacent pair of squares or rectangles on the bottom surface of the tension relief pad is of uniform size.
 9. The tension relief mattress of claim 1, wherein the tension relief pad is made of polyurethane foam.
 10. The tension relief mattress of claim 1, wherein a spacer fabric is located between the tension relief pad and the innerspring unit.
 11. A tension relief mattress system comprising: an innerspring unit having a plurality of interconnected coils; a tension relief pad having a top layer which is substantially planar and a bottom layer, opposite the top layer, which contains a plurality of cuts formed into a plurality of raised blocks; wherein the thickness of the plurality of raised blocks is at least one inch, the width of the plurality of raised blocks is greater than or equal to the block height and the distance between each adjacent pair of the plurality of raised blocks is approximately 15% of the smallest block width.
 12. The tension relief mattress system of claim 11, wherein the size of the plurality of raised blocks is uniform.
 13. The tension relief mattress system of claim 11, wherein the size of the plurality of raised blocks is non-uniform.
 14. The tension relief mattress system of claim 11, wherein the size of the plurality of foam blocks corresponds to one or more coils of the innerspring unit.
 15. The tension relief mattress system of claim 11, wherein the tension relief pad is made of polyurethane foam.
 16. A tension relief mattress system comprising: an innerspring unit having a plurality of interconnected coils; a comfort unit comprising two or more foam layers and a tension relief pad positioned between the two or more foam layers, the tension relief pad having a top surface which contains a plurality of cuts formed into a plurality of raised blocks; wherein the thickness of the tension relief pad is at least one inch, and wherein the tension relief foam pad is laminated.
 17. The tension relief mattress system of claim 11, wherein the size of the plurality of raised blocks is uniform.
 18. The tension relief mattress system of claim 11, wherein the size of the plurality of raised blocks is non-uniform.
 19. The tension relief mattress system of claim 11, wherein the tension relief pad is made of polyurethane foam.
 20. The tension relief mattress system of claim 11, wherein the height of the plurality of raised blocks is at least 2.5 inches. 